Possums

Angry possum. Photo: Animal Health Board.
Angry possum.

In its native land the possum is up against dingoes, bush fires and less palatable vegetation. In New Zealand there are no predators and lots of very palatable vegetation. As a result, possums have a huge impact on New Zealand ecosystems.

The Australian brush tailed possum was introduced into New Zealand in 1837 to establish a fur trade.

Description

The possum has a thick, bushy tail, a pointed snout and long, fox-like tapering ears. Size and weight of possums varies greatly across New Zealand. Adult possums are typically between 65 and 95 cm in length, and can weigh anywhere between 1.4 and 6.4 kg.

There are two general colour forms, grey and black, although each of these varies greatly.

  • Grey possums are generally a clear grizzled grey on the body, with the face pale grey, darker around the eyes and on the side of the snout, and white at the base of the ears.
  • Black possums are generally a deep, yellowish-brown, tinged with rusty red. The ears have little or no white at the base and the tail is nearly entirely black.

The sternal gland stains fur on the throat and chest a dark rusty red, more prominently in males than in females, and more prominently in grey than in black possums.

Behaviour and life cycle

Possum eating a chick. Photo: David Mudge. Copyright: Nga Manu Images.
A possum eating a chick it has taken
from the nest

Possums can live anywhere that has shelter and a varied food supply. They can be found all across New Zealand, with the exception only of the high rainfall, mountainous terrain of Fiordland. Forests are the major habitat, especially hardwood mixed forests, where possum densities are particularly high. Forest/pasture margins are also known to support very dense populations.

While possums feed mainly on leaves, they are also known to take:

  • buds and flowers
  • fruits
  • ferns
  • bark
  • fungi
  • invertebrates
  • native birds and eggs
  • land snails
  • carrion

Possums are nocturnal, although in winter starving or sick animals may emerge to feed in the afternoon.

The threat

Possum damage on Mamaku, Pirongia Forest Park. Photo: Keith Broome.
Possum damage on Mamaku, Pirongia
Forest Park

The damage to native forests can be seen all too clearly in many areas. Possums ignore old leaves and select the best new growth. In some areas they have eaten whole canopies of rata, totara, titoki, kowhai and kohekohe.

Possums compete with native birds for habitat and for food such as insects and berries. They also disturb nesting birds, eat their eggs and chicks and may impact on native land snails.

Dairy and deer farmers have the added worry of possums spreading bovine tuberculosis.

Possums are a nuisance in suburban gardens, and sometimes even indoors.

Stoats and possums eat kea video

Evidence shows stoats and possums are eating kea. Researchers using nest-cameras have for the first time witnessed the gruesome reality inside defenceless kea nests invaded by stoats and possums in South Westland. Find out more abut possums eating kea.

Video by Trakabat

Carol Nanning (DOC staff) sitting in a helicopter used for aerial possum control, Coromandel. Photo: Justine Cannon.
Carol Nanning (DOC staff) sitting in a
helicopter used for aerial possum control

DOC's work

DOC is charged with the care of New Zealand's native plants and wildlife. Possums are a threat to these values and in fact, the survival of whole ecosystems is affected by the possum.

The Department of Conservation commits resources to possum control at priority sites to ensure long-term survival of species and the ecosystems that support them.

  • Pest control
  • 1080 for pest control
  • View videos about controlling possums with 1080
  • You can help

    Signs that possums are present

    Tracks (‘pads’ or ‘runs’) are often most evident where possums emerge from forests to feed on pasture. They are also visible in forests when possum numbers are high.

    Frequently used trees show extensive surface scratches. Bark biting, usually a series of horizontal scars, can be seen on a variety of native and introduced trees and shrubs. Often the same trunk, marked repeatedly, becomes heavily scarred.

    Faecal pellets are usually about 15-30 mm long, 5-14 mm wide, crescent shaped slightly pointed at the ends and found singly or in groups; colour and texture vary with diet. Leaves browsed by possums have torn rather than cut edges, with the midrib and lower part of the leaf often partly remaining, unlike insect browse.

    Possums are distinctive feeders, leaving the ground littered with broken branches, discarded leaves, or partly eaten fruits of native plants.

    Dark brown urine trails may be seen, particularly if possums have been feeding on kamahi or five-finger, both of which stain the urine.

    Control methods 

    Hunting/shooting, trapping and poisoning are the main methods of control for possums.

    Training

    If you are planning a pest control operation enrol for the Animal Pest Control Methods field based course.

    The course provides an overview of animal pests, their impacts and control methods (including the principles these are based on, and the task specifications DOC has developed).

    The course covers all the legal requirements for animal welfare and handling toxins. Working within the law is vital to allow pest control agencies and community groups continued access to the full suite of animal pest control methods.

    In particular, it describes the control methods most commonly used in DOC, and their advantages and disadvantages.

    Monitoring your control

    All operations require monitoring below are examples of methods used.
    Learn more about monitoring

    Residual trap catch index

    A method for estimating possum abundance based on sampling populations by means of traps.

    Wax tags

    A method for estimating possum abundance based on sampling populations by means of interference with "wax tags" (scented ice-cube sized wax blocks).

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